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Baseline Calibration

This calibration procedure involves identifying a specific period during which the sensor is exposed to a minimum reference gas concentration, preferably zero concentration of the targeted gas. The calibration parameters are then adjusted based on this condition..
In order for this procedure to work, you need to make sure that you have already uploaded a reference data of the targeted gas. If you haven’t done this step kindly click this link for more details.

Calibration Steps:

  1. Select Device and Reference Station
      • In this step, you need to select following:
        • Type - refers to calibration type. Select “Baseline”.
        • Installation - refers to your device installation
        • Gas Sensor - refers to the sensor you want to calibrate
        • Reference Station - refers to the reference station / device that contains the reference data of the targeted gas.
Figure 1 - Select Device and Reference Station
Figure 1 - Select Device and Reference Station
  1. Select the period with the lowest reference concentration
      • In this step you will be shown with a graph showing the reference data of the targeted gas (Green line - Reference Data Red line - Original values).
      • Using the green line series, find a period when the reference value is at its lowest or minimum, by highlighting that period on the chart.
      Figure 2 - Select period with lowest concentration
      Figure 2 - Select period with lowest concentration
      • An “Analyze” button will be shown on the screen. Kindly review if the selected period is correct, before clicking it.
        • B1 - B2
      Figure 3 - Analyze button is shown
      Figure 3 - Analyze button is shown
      • After clicking analyze, the calibration tool will compute for the baseline offset based on the period that you have selected. The following options will be provided to you:
        • Baseline Offset based on the minimum concentration
        • Baseline Offset based on the average / mean
        • Or enter your preferred offset (don’t forget to click “use” to use the value from this field)
      Figure 4 - Pick an offset
      Figure 4 - Pick an offset
  1. Select your preferred offset
      • When an offset is selected or defined, a new series will appear on the chart, and will be called “Corrected Values”. This series represents the adjusted values based on the offset that you have selected. It will appear as a “blue” line.
      • A Pearson correlation chart will also appear to show the linear relationship between the reference data and the corrected values.
Figure 5 - Corrected values
Figure 5 - Corrected values
  1. Apply Calibration
      • Once you’re done selecting the baseline offset, you can apply it to the gas sensor by clicking the “Apply Calibration”.
      • This will send request to the server that you want to apply the selected baseline offset to the “offset constant” of the gas sensor settings.
      • The request will be applied on the next polling interval of the device.
Note: At the end of the baseline calibration, you will be asked if you want to further calibrate the sensor and proceed with the span calibration. If you click “yes”, the baseline offset that you have selected will be carried over to that process.
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